Could a Drone Disruption Like Gatwick’s Happen at a U.S. Airport?

Two drones that went floating over a runway at Gatwick Airport outside London this week caused chaos, disrupting hundreds of flights there, and stranding tens of thousands of passengers at England’s second-largest airport and elsewhere at the peak of the holiday season.

The drone disruption raises a host of questions, but for travelers in the United States, perhaps the most pressing is this: Could it happen here?

Here’s what we know.

What exactly happened at Gatwick?

Airport staff members first spotted the drones flying over a perimeter fence and into the runway area around 9 p.m. on Wednesday. Officials shut the runway, and then reopened it around 3 a.m. Thursday before closing it again about 45 minutes later when there was another sighting. Yet another drone was spotted late Thursday morning, and people kept spotting drones into Thursday night.

Officials called the move a “deliberate act,” but the police said there were “no indications to suggest this is terror related.”

The shutdown canceled at least 800 flights, disrupted traffic throughout Europe and could end up affecting upward of 100,000 passengers. Arriving flights carrying 10,000 passengers were diverted, with some travelers forced to land at airports as far away as Paris.

Could this happen in the United States?

Airports in Chengdu, China; Dubai, the United Arab Emirates; and Ottawa have also had to shut down because of drone sightings.

But although drones have been seen hovering above American airports, it does not appear as though any of them have been shut down as a result. And certainly nothing quite like what happened in England has “happened anywhere in the world before,” said Richard Gill, the founder and chief executive of Drone Defence, an airspace security company.

Guidance from the Federal Aviation Administration says: “Generally, drone operators should avoid flying near airports because of other air traffic. It is very difficult for other aircraft to see and avoid a drone while flying, and drone operators are responsible for any safety hazard their drone creates in an airport environment.”

But Luke Fox, the founder and chief executive of WhiteFox, a drone airspace security company, said drones frequently fly near airports. “Every single airport we’ve deployed our technology at, we’ve seen it happening daily,” he said. “The only difference is that they saw the drone this time.”

Asked whether an episode similar to what happened at Gatwick Airport could happen in the United States, Mr. Fox said: “Yes, absolutely. People will unfortunately see this and recognize there’s a vulnerability here.”

What are the rules?

As drones emerged in the public consciousness, a hodgepodge of federal, state and local regulations surfaced, leaving many rules undefined or murky. But in October, the rules were streamlined when Congress approved — and President Trump later signed — the F.A.A. Reauthorization Act of 2018. That law provides the Department of Homeland Security and the Justice Department with “authorities to counter unmanned aerial systems used for nefarious purposes,” according to a Homeland Security statement.

The episode at Gatwick Airport demonstrates that drone operators’ “intent to cause disruption or harm” can create “significant risks to the safety and security of the populace,” McLaurine Klingler, a Homeland Security spokeswoman, said in a statement to The New York Times. “The authorities Congress has provided to specific federal departments and agencies are vital to protecting the public.”

The law asks the F.A.A. to enact safety provisions like a mandatory quiz that new drone users must pass before flying and a remote identification system that traces a drone back to the location of its owner.

Adam Lisberg, a spokesman for D.J.I., a prominent drone manufacturer, said the Gatwick episode would increase the F.A.A.’s urgency to carry out the law. “I’m sure the Gatwick incident is going to spur them to try to speed up their timetables,” he said. “They are already well aware of how quickly they need to move.”

What else is being done to defend against drones?

Technology companies have invented several antidrone defense systems, but they are relatively new, and airports and government officials are still weighing which to invest in.

Tim Bean, the founder and chief executive of Fortem Technologies, which is testing its own drone defense system on several American runways, said that “over 90 percent of airports in the world are unprepared for drones.”

“Airports, stadiums, borders, oil and gas refineries — they spend a lot of money on ground security, but I think they now need to think about their airspace security.”

A system developed by Mr. Bean and Fortem Technologies uses a sophisticated radar system to detect intruder drones, and then sends a drone hunter to pluck them out of the sky or dogfight with them if necessary. The system is already being used to monitor two runways at Salt Lake City International Airport and others.

D.J.I. has already introduced a tracking system, called Aeroscope, that Mr. Lisberg said would eventually act as a major deterrent toward improper use. “If you’re flying a drone in an improper way in a sensitive location, you can expect to have a squad car pull up on you pretty quickly,” he said.

The company is also working to improve geofencing, a technology that prevents drones from flying above sensitive areas. “It’ll feel like the drone is hitting an invisible wall in the sky,” Mr. Lisberg said.